Load Specifications
Load data in caliber .45-70 Govt. with .458 | 350gr | Hornady InterLock RN bullet and 4 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 14 and Hodgdon TrailBoss.
Important Notice: DO NOT go below Minimum Charge or above Maximum Charge. Since we have no control over the equipment and components used, any responsibility and liability for the results achieved is rejected.
Only powders/loads that match the current filter criteria are displayed: max pressure of a load ≤ 90% of max. standardized pressure, fill rate ≥ 80% and propellant combustion ≥ 95%. Use the sliders above the tables to adjust these thresholds.
Charge: Powder weight in grains. Start with the minimum load and work up carefully.
FR (Fill Rate): Case fill as a percentage. Values above 100% mean compressed loads.
MaxP / %: Maximum chamber pressure in bar and as a percentage of the standardized maximum for this caliber.
V(0): Muzzle velocity in feet per second (fps) at the standardized barrel length.
z (Powder Burn): Estimated propellant combustion percentage at bullet exit.
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Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 82% | 28,152 psi | 88% | 1896 fps | 98.5% |
| Hodgdon TrailBoss | <<locked>> | 98% | 28,572 psi | 90% | 1266 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 98% | 28,195 psi | 88% | 1299 fps | 100% |
| Vihtavuori N120 | <<locked>> | 82% | 28,514 psi | 89% | 1873 fps | 99.3% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| ADI AR 2207 | <<locked>> | 80% | 26,368 psi | 83% | 1857 fps | 97.9% |
| Hodgdon TrailBoss | 14.7 gr | 80% | 21,509 psi | 67% | 1145 fps | 100% |
| ReloadSwiss RS 14 | 15 gr | 80% | 21,176 psi | 66% | 1171 fps | 100% |
| Vihtavuori N120 | <<locked>> | 80% | 26,731 psi | 84% | 1837 fps | 98.9% |
Recommended = one of the top powders for this cartridge and bullet combination.
This overview compares 4 powders for .45-70 Govt. loaded with the .458 | 350gr | Hornady InterLock RN. ADI AR 2207 delivers the highest muzzle velocity at 1,896 fps; across all powders the maximum-charge window runs from 1,266 fps to 1,896 fps. Hodgdon TrailBoss gives the best case fill at 98 %, and 4 of the 4 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (220 MPa), the top charges use 88–90 %, leaving at least 10 % headroom. ReloadSwiss RS 14, Hodgdon TrailBoss rank at the top here: for .45-70 Govt. with the .458 | 350gr | Hornady InterLock RN they combine a high case fill with complete burn and sit in the upper velocity band. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.